Now i'm looking for a cornerstone against everything else. Maybe even the 1. c4 / 1. Nf3 "for starters" stuff in the book mentioned above coult be needed to get more details?!

Looking for books on that topics i find "Grandmaster Repertoire: Beating Minor Openings" by Victor Mikhalevski and the 2007 book "Beating unusual chess openings" by Richard Palliser. One is maybe too advanced for me with 1800 Elo the other one is rather outdated.

Of course i could subscribe to that flank openings section on chesspublishing und hopefully find some guide there to build up something on my own?